Elevator control system



Oct. 6, 1942. w. F. EAMES A 2,298,111

ELEVATOR CONTROL SYSTEM 2 SheeLs--SheeiI l Filed Aug. 19, 1941 d 5,/BWZM ATTNEY Oct. 6, 1942. w F EAMES I 2,298,111

ELEVATOR CONTROL SYSTEM FiledrAug. 19, 1941 2 Sheets-Sheet 2 1J M eE11/1D /P 2F34 mr fc w UF6/751 Bpdrap l l l j 20L apen.; Z/Odra/zs.

Patented Oct. 6, 1942 UNITED STATES PATENT OFFICE ELEVATOR CONTROLSYSTEM William F. Eames, Westfield, N. J., a'ssignor to WestinghouseElectric Elevator Company, Jersey City, N. 1., a corporation of IllinoisApplication August 19, 1941, Serial No. 407,414 (ci. 172-152) 14 Claims.

Another object is to provide a leveling and releveling system which willrequire the use of less complicated floor selectors and circuits thanthose heretofore found necessary for use in leveling and relevelingsystems.

A further object is to provide a. system which will automatically causean elevator car, in making a one-floor run, to accelerate to its mostdesirable speed, then decelerate at its most desirable rate for aone-iloor run when the car switch is moved to its on position and thenpromptly returned to its center or "nl f position.

A still further object is to provide a system in which compensation maybe made for temperatur'e changes which ailect the leveling action.

It is also an object to so control the energization of the generatorsembodied in variable voltage elevator systems as to secure the mostdesirable deceleration of the elevator cars when making stops at theiriloor levels.

Other objects will become apparent from the following description of theinvention taken in conjunction with the accompanying drawings. in which:

Figure 1 is a diagrammatic representation in what is known as thestraight-line style of control system for an elevator car embodying myinvention;

Fig. 1A is an explanatory illustration of the relays embodied in thecontrol system of Fig. lthe illustration shows the relays with theircoils and contact members disposed in horizontal alignment with theirpositions in straight-line circuits oi Fig. 1, so that the identicationof -any relay and the position of its coil and contact members in thestraight-line circuits may be readily determined;

Fig. 2 is a diagrammatic representation of an inductor relay to/ bemounted on a car and a pair of inductor plates therefor mounted upon thewalls of the hatchway in which the car operates as looking from the car;and

Fig. 3 is a reduced view in side elevation of the inductor relay shownin Fig. 2.

the hatchway Wall toward Y The relays embodied in the system aredesignated as follows:

U =up direction switch D :down direction switch UR:up direction relay orcontrol device DR:down direction relay or control device M :car runningrelay N :auxiliary car running relay GR=high speed start relay 1P :lowspeed decelerating relay 2P :intermediate speed decelerating relay '3P:high speed decelerating relay L :leveling inductor relay LU=up levelingrelay LD=down leveling relay TA:time delay relay for one-floor runsTB=antiplugging relay TC:smooth-start relay Q :counter-electromotiveforce relay K :door-operating relay.

Referring more particularly to the drawings, I have illustrated a car Cfor serving a plurality of landing floors as suspended by a suitablecable Il which passes over a hoisting drum I2 to a suitablecounterweight i3. A hoisting motor H is provided for operating thehoisting drum by means of a shaft Il to raise and lower the car. 'I'hehoisting motor H is provided with a eld winding HF which is connectedfor constant energization to a pair of supply conductors L+ and L-,which may be connected to a supply of electrical energy by a pair ofline switches l5 and I6.

A variable voltage system of control is provided for controlling theoperation of the hoisting motor H, wherein the hoisting motor armatureHA is connected in a closed circuit 2| with the armature GA of agenerator G. The generator is provided with a separately excited fieldwinding GF which is connected for energization in a loop circuit 22 withthe armature RA of a regulator R, so that the output of the generatorand, consequently, the speed and direction of operation of the hoistingmotor H may be controlled by controlling the operation of the regulator.An adjustable resistor rl is connected in the circuit of the generatorfield winding for adjusting the resistance of that circuit to anydesired value. A commutator pole winding 24 for the generator G isconnected in series in the loop circuit 2|. The armatures of thegenerator and the regulator may be mounted on a common shaft 26 foroperation by any suitable constant speed motor (not shown).

The regulator R is provided with a self-exciting iield winding RCF, apattern eld winding RPF, a differential eld winding RDF, and a serieseld winding RSF.

The self-exciting iield winding RCF is conlnected in the loop lcircuit22 in series with the regulator armature RA and the generator iieldwinding GF. The total resistance or' this circuit should be made equalto the volts that the regulator will produce when one ampere howsthrough its self-exciting field winding. It has been found that withthis adjustment perfect regulation will be obtained with no huntingeffects.

The pattern eld winding RPF is disposed to be connected across thesupply conductors L+ and L-, so that the generator voltage and thedirection of operation may be controlled by con-y trolling the directionand the value of the current in the pattern field. For a givenexcitation of the pattern iield, the regulator will produce a voltagewhich will excite the generator field winding GF. As soon as currentstarts to ow through the generator field winding circuit, theself-exciting iield winding RCF excites the regulator to force thecurrent through the generator field winding. Y

A plurality of resistors rt to ri@ are connected in the circuit of thepattern held winding to so control the value of that winding that thegenerator G will be energized to cause the car to accelerate, run anddecelerate at predetermined desired speeds. Y

The differential field winding RDFis connected across the terminals ofthe generator armature GA. An adjustable resistor ril is inserted inseries with the differential field winding RDF, 'so that the value oithe dierential :deld wind ing may be adjusted as desired. Thisdiierential iieid winding and the pattern ileld winding RPF are adjustedto produce the same and opposite voltage in the regulator tor a givenexcitation or the pattern field. i

The regulator series field RSF is connected in series in the loopcircuit 2l between the armatures or the generator and the hoistingmotor. rihis field winding is provided to cause the regulator to givethe generator neld winding suril= cient excitation to compensate for them drop in the hoisting motor. The regulator R is disclosed and claimedin Danilo Santini Patent Nm 2,221,610, granted November l2, 1940, andassigned to Westinghouse Electric Elevator Conipany. Further detailsregarding the regulator and its functions, if desired, may be secured inthe patent.

An electromagnetic brake l@ having a coil iQa is associated with theshaft i5 for stopping and holding the car when the power to the hoistingmotor is out on. A pair of resistors vll and f5 are disposed in thecircuit of the coil ita to cause a quick brake action under certainconditions hereinafter donned.

A car switch CS is mounted in the car for use by the car attendant tostart and stop the car. The car may be started in the up direction bymoving the car switch counter-clockwise and in the down direction bymoving it clockwise. When the ear switch is centered, it causes the lcar to stop at the next door.

The up direction switch U and the down direction switch D control theenergization. of the generator G hy connecting the pattern iield windingof the regulator to the supply conductors L+ and L- for'up direction ordown direction operation.

The car running relay M is controlled by the direction switches U and D,and is provided for controlling the brake IS and preparing certaincircuits for operation when the car switch is thrown for movement of thecar.

The auxiliary car running relay N ls controlled by the relay M, and isprovided for further preparing the control system for operation afterthe action of the car running relay M.

The high-speed starting relay GR is controlled by the direction switchesU and D, and'ls prountil the car has gotten started at low speed Therelay TC should have a time delay of ap proximately .3 second in openingafter it is deenergized.

The door relay K is provided for controlling the door operating motor(not shown) to cause it to open the doors at a floor when the car mairesa stop thereat, and to prevent it rrom .opening the doors while the car.is running or is conditioned to start.

The counter-electroniotive force relay Q is connected across the loopcircuit 2i to prevent operation oi the door relay E to open any doorwhile the hoisting rnotor is operating above a predetermined low speed.

vany suitable landing system for causing the carto stop level with thefloor after the car switch is centered ior a stop may be employed.However, l have illustrated as one suitablesystem the automatic inductorrelay system described and claimed in the copending application ofDanilo Santini, died Sept. d, wel, Serial No. 409,491, and assigned tothe Westinghouse mectric Elevator Company. This landing system includesthe inductor relay L which may be mount ed on top of the elevator car Cvin position to come adjacent to an up inductor plate E and a down'inductor plate F mounted on the walls of the hatchway (not shown) ateach oor landing by means of a plurality o angle braces 23. In thisparticular illustration it will he assumed that the inductor plates Eand F are each about 2l inches long and that the inductor relay is about'7 inches long, The plates should he so mounted in vertical, overlappingposition in the hatchway, and the inductor relay L should be so mountedon the car that the relay will pass between the plates and close to themwithout touching them as the car moves up and down in the hatchway.Furthermore, the relative position of the relay and the plates should besuch that if the car oor is level with oor landing at which the car isstopped, the center of the relay, as indicated by the line x--x will bemidway between the upper end of the inductor plate F and the lowerend'of the inductor plate E, as shovm in Fig. 2.

The inductor relay is provided with two pairs of contacts EUL and HDL onim upper end and with two pairs of contacts IUL and ZDL on its lowerend. An amature 32 is provided for each pair of contacts. The armaturesfor operating the contacts ZUL and IUL should be disposed in position tobe operated by the inductor plate E and the armatures for operating thecontacts 2DL and IDL should be disposed in position to be operated bythe inductor plate F when the coil of the relay is energized and the carmoves the relay into position adjacent the inductor plates.

Although the drawings illustrate the plates E and F for only one iioorlanding, it is to be understood that a set of these plates is mounted ateach oor served by the car and that they will be effective to stop thecar only when the coil of the inductor relay L is energized to cause thecar to stop.

The inductor contacts are normally closed and when the car comes down toa stop at the oor level the contacts open in the following order: IUL,2UL, 2DL and IDL, When the car comes to a stop at the floor level, thecontacts open in the following order: IDL, 2DL, ZUL and IUL.

y 'I'hese actions deenergize the speed relays in the order 3P, 2P, IPand the appropriate direction switch regardless of the direction oftravel.

The high speed decelerating relay 3P controls the deceleratingresistance r2 included in the circuit of the regulator series iieldwinding RSF, the resistance r3 in the regulator differential fieldwinding RDF, and the resistor 1'8 in the circuit of the regulatorpattern field winding RPF to cause the car to decelerate from high speedto intermediate speed.

The intermediate speed decelerating relay 2P controls the resistance r9in the regulator pattern ileld winding RPF and also conditions thecircuits for switches U and D, and relays yM and N.

The 10W speed decelerating relay IP controls the resistance rIII in thecircuit of the regulator pattern eld winding RPF and the use ofresistances r4 and f5 in the circuit of the brake coil I9a.

The time delay TA has a time delay of approximately 1.8 seconds whenopening and is designed to provide a holding circuit for the updirection relay UR or the down direction relay DR when the car switch isthrown to its. starting position and immediately returned to its centerposition for a one-floor run` This time delay relay holds the up or thedown direction relay UR or DR energized for the amount of time necessaryto cause the car to make a one-floor run. Under this predeterminedset-up, the car will accelerate to and run at its high speed for aone-iloor run and then decelerate at the proper time to a stop at thenext floor.

The up leveling relay LU and the down leveling'relay LD are controlledby the up contacts IUL and the down contacts IDL on the inductor relay Lto cause the car to relevel if it rises above or sinks below the floorlevel at the landing at which it is stopped. If the car moves up for,say, 1/2 inch the contacts IDL will pass beyond the upper end of theplate F and will thereby be operated to cause the down direction switchD to move the car down to its floor level. vOn. the other hand, if thecar moves down, say, 1/2 inch below the oor, the contacts IUL will beoperated by passing beyond the lower end of the plate E to operate theup direction switch 4 ,to cause the car to return upwardly to its floorlevel. Obviously, when the car returns to its correct level position itwill so position the inductor relay L that all its contacts will bewithin the limits of the conductor plates E and F, and none of them willthen operate to control the car.

(Sil

The anti-plugging relay TB is provided with a time delay ofapproximately .3 second and operates to prevent energization of theinductor relay L when the car is traveling at full speed and for afraction of a second after retardation starts so that the relevelingswitches cannot plug the hoisting motor at too high a speed.

'I'he relay 3P is also provided with contacts 3PA in the circuit of theup direction relay UR and DR which permits the release of the one floorrun holding circuit provided by the relay TA whenthe car is closer to afloor than its normal one-iloor run distance when it is started towardthat oor.

It is believed that the invention will be best understood lby thefollowing assumed operation of the system illustrated in the drawings.It should be noted, however, that the particular dimensions, periods ofdelay, amounts of resistance involved, etc., are given as anillustration of what may be included in an operating system but thatother values may be readily used in adapting the system to meet variousoperating conditions.

It will be assumed that the switches I5 and I8 are closed to prepare thecontrol circuit for operation. This action energizes the hoisting motoreld winding HF, the inductor relay L, the one-floor run relay TA and thesmooth start relay TC. It will be assumed that the car is starting atthe eighth floor landing level with the door. Therefore, the inductorcontacts IUL, 2UL, IDL and 2DL are all operi because of the energizedcondition of the inductor relay L and its position between the inductorplates E and F for that floor (see Fig. 2).

It will be assumed now that the car attendant, desirous of making aone-iioor run, closes the car switch CS in anti-clockwise direction tomove the car down to the next floor. Inasmuch as this is tov be aone-floor run, the attendant will close the switch only temporarily andthen return it to its oil' position. The length oi' time the switchstays closed is not critical, but it must @be centered before the carruns more than one- L+, URS, DR, 33, L-

The energized down direction relay DR opens its Ibaci: contacts DRI andDR3 and closes its front contacts DRI, DR4, DRS and DRB. The closing ofthe contacts DRE energizes the door relay K to cause the door motor (notshown) to close the car gate and the iloor landing door (not shown). Theclosing of the contacts DRZ prepares the circuit of the down directionswitch D for operation. The closing of the contacts DR4 prepares thestarting relay GR for operation. The closing of the contacts DRSenergizes the anti-plug ging relay TB.

The energized anti-plugging relay TB opens its back contacts TB3 thusdeenergizing the inductor relay L which causes the decelerating andleveling contacts IUL, 2UL, IDL, 2DL on the inductor relay to reclose,thus energizing the de-A celerating relays IP and 2P and the levelingrelays LU and LD which will remain in that condition until the next stopis to `be made. This operation of the decelerating relays short circuitsthe decelerating resistors in the pattern field circuit to condition thedecelerating means for action when the car is to be stopped.

It will Ibe assumed now that the door motor has closed the car gate and.the landing ioor door thereby operating a limit switch (not shown) tostop the door motor and also closing the car gate and door safetycontacts d@ and di.

The closing of the contacts t@ and il completes the circuit forenergizing the down direction switch D through L+, D, Us, par, te, sa,una, L-

'I'he energized down direction switch D closes its front contacts DI,D2, Dl, D5, DS `and D@ and opens its back contacts D3, Dl and D3. Theclosing of contacts D5 completes a self-holding circuit for the downdirection switch D. The closing of the contacts Dit energizes the carrun-Y ning relay M by the circuit L+, M, Dit, DRE, l, M, URE

The .closing of the contacts DI and D2 prepares the pattern eld windingRPF for operation in the down direction.

The closing of the Contact members D9 energizes the decelerating relay3P by the circuit L+, LUs, De, s?, L-

The relay 3P opens its contacts SP2 around the resistor r3; opens itscontacts SPE to insert the resistor r2 in series with the regulator:Held winding RPF, and closes its contacts 3P3 to short circuit theresistor rd in the pattern circuit. These connections are prepared tosecure certain desired operations during deceleration of the car as willbe described later when the car is decelcrated to a stop at the nextfloor.

Returning now to the energized car running relay M, that relay opens itsback contacts Mi and closes its front contacts M2, M3 and MAG. Theopening of the contacts Mi inserts the resistor r3 in series with theregulator differential field winding RDF for a purpose to be describedlater. The closing of the contacts M2 prepares the brake coil lila foroperation. The closing of the contacts completes the circuit through thepattern iield winding RPF for the down direction as follows: L+, D2,RPF, Di, M3, r6, rl, TCB, L-

The energized relay N closes its front contacts Nl and N2 and opens itsback contacts N3 and Nd. The closing of the contacts Ni energizes thegenerator field winding GF by the circuit RA, RCF, Ti, GF, Ni

The generator now starts to deliver energy to the hoisting motor foroperating the car downwardly. At the same time, the relay N closes itscontacts N2 thereby energizing the brake coil i230; by the circuit L+,Na, en, sec, M2, n

The energization of the coil i9@ releases the brake i9 and the carstartsto move downwardly. The opening of the contacts Ni deenergizes thesmooth start relay TC and after the expiration of .3 second that relayopens its contacts TCI which aaeaiii of the pattern field for startingpurposes in order vto secure a smooth start. The deenergization of therelay TC also closes its back contacts TCZ which thereupon complete theenergization of the starting relay GR by the circuit thereby shortcircuiting the resistors r1, T8, r9

and ri in the pattern eld winding RPF. This increases the energizationof the pattern iield circuit which causes the generator G to increasethe speed of the hoisting motor H to its high running speed.

The car is moving downwardly now but it will be recalled that the oneloor run relay TA was deenergized by the opening of the contacts N3 whenrelay N was energized. The relay PA will now, at the expiration of 1.8seconds, when the car is about half way between the oors, operate toopen its contacts TAI which were holding the down direction relayenergized. It will be recalled that the car switch was closed onlytemporarily and that, therefore, the only circuit for the down directionrelay DR passed through the contacts TAE. Therefore, the present openingof these contacts deenergizes the down relay DR which thereupon closesits back contacts DRI and DRS -and opens its front contacts DR2, DRl,DRS and DB6.

The opening of the contacts DRl deenergizes the starting relay GR whichthereupon opens its contact members GR! to eliminate the short circuitaround the resistors rt, rl, T8, r9 and rli.

had included the resistors 1'@ and rl in the circuit 75 However, it willbe observed by the drawings that inasmuch as the decelerating relays IP,2P, and 3P are energized, the resistors f8, r9 and ri now stand shortcircuited by the decelerating contacts, but that the resistors r6 and rare completely included in the pattern field circuit. The effect of theresistors r6 and rl is to reduce the speed of the car as it approachesthe iirst point at which the inductor relay L starts decelerating thecar. This point will be the upper end of the plate E and will correspondto a position of the car approximately 21 inches from the next oor.

Theropening of the contacts DB5 deenergizes the anti-plugging relay TBwhich, after the expiration of a .3 second delay, closes its backcontacts TBS thereby re-energizing the inductor relay L so that as it isbrought opposite to and moved along the inductor plates E and F, its contacts will be operated sequentially to decelerate the`carto a down stopat the seventh floor.

As the car approaches to the point approxirnately Z1 inches from the oorlanding, the inductor relay L approaches the inductor plate E, and asthe contacts iUL come exactly opposite the upper end of the plate E,they are operated by the ux induced in the plate through the energizedrelay, to move to their open position, thus deenergizing the levelingrelay LU to open its front contacts LUI and LUS and close its backcontacts LU?. The opening of the contacts LUS deenergizes the high speeddecelerating relay 3P which thereupon opens its contacts 3123 thusinserting the resistor 18 in the circuit forthe pattern eld winding todecelerate the car from its high decelerating speed to its intermediatedecelerating speed.

At the same time, the deenergized relay 3P recloses its contacts 3Pa, toshort circuit a portion of the resistor r3 in series with thedifferential field winding RDF thereby strengthening that' regulatorfield winding for the purpose of rendering the deceleration moreeffective. This action may be described as producing a tendency tohuntin the regulator but the action is directed cppositely to the carsmovement so that the carretards at a higher rate than normal. It wouldultimately reverse its direction of travel except the brake appliesquickly when the car reaches oor level. which holds the car at iloorlevel and prevents reversal.

Also at the same time the deenergized relay 3P recloses its backcontacts SPI and short circuits a portion of the resistor r2 in circuitwith the series eld winding RSF to strengthen that series field windingto keep' the regulation ilat.

As the car decelerates from its high decelerating speed to itsintermediate speed, it approaches to within approximately 14 inches ofthe down stop at the seventh iloor and thereby moves the energizedinductor relay L downto such a point that its contacts IUL come oppositethe upper edge of the plate E and are operated to open position by theinduced flux passing throughthe plate and the armature attached to thecontacts. The opening of the contacts 2UL deenergizes the deceleratingrelay 2P which thereupon opens its contacts ZPI, 2PZ, and ZPB.v Theopening of the contacts 2PI re-inserts the resistor f8 in the circuit ofthe pattern field of the regulator thus causing the regulator todecrease the amount of power supplied to the generator and therebydecrease the speed of the hoisting motor H and the car C fromintermediate speed to low speed.

As the car approaches still closer to the seventh floor, the counterelectromotive force relay Q is operated to open its contacts QI- in thecircuit of the door relay K to prepare that relay for operation.

As the car drops still lower and arrives at a point about 7 inches fromthe seventh floor, it moves the energized inductor relay L downwardly toa point where its contacts 2DL come opposite the top of the inductorplate F and are thereby operated to their ope'n position, thusdeenergizing the decelerating relay IP to decelerate the car to landingspeed. The deenergized relay P opens its contact members IP4 in thecircuit of the door relay K and also opens its contacts IPI to reinsertthe resistor rIIJ in the circuit of the pattern field which reduces thespeed' of the hoisting motor to what is known as stopping speed(approximately 15 feet per minute).

The deenergized relay IP also opens its contacts IPZ and IP3 in thecircuit of the brake coil I9a thereby reinserting the resistors r4 andf5 in the brake circuit to weaken the brake coil for a quick dropout. Itwill be noted that the contacts BK operated by a mechanical switch (notshown) on the brake still remain open because the brake is still inreleased condition, thereby rendering effective the operation of thecontacts IP2 and IPS.

As the car approaches closely to the floor and the iioor of the carcomes within, say, one-half inch of the iloor level of the landing, theenergized inductor relay L carries its contacts IDL the regulatorpattern field circuit and causing the hoisting motor to stop. Theopening of the contacts LDI also deenergizes the car running relay M andthe auxiliary car relay N. Thereupon the deenergized relay N opens itscontacts N2 thus applying the brake I9 to prevent further operation ofthe hoisting motor and the car.

The car is now stopped level with the oor because the operation of theinductor relay contacts IDL, as the car arrived within one-half inch ofthe floor, caused the shutting of! of the power and the application ofthe brake lto stop the car at the instant it leveled with the iloorlanding. l

The deenergized relay N also recloses its back contacts N3 and N4thereby reenergizing the one-oor run relay TA and the smooth start relayTC so that they will be ready for use when next needed in the operationo1' the car.

It should also be noted that the deenergization oi the car running relayM closes its back contacts MI thereby eliminating all of the resistor r3from the circuit of the dierential iield winding RDF which gives thatileld full killing strength for any residual magnetism in the armatureHA o! the hoisting motor. Also the deenergized relay N opens its contactmembers NI in the circuit of the generator field winding GF to stop theow of energy through that field winding.

The car has new completed its one-run operation to a stop at the seventhoor.

The foregoing assumed action illustrates how my improved control systemoperates to cause the car to make a one-oor run in response to an overand back operation of the car switch in which the car attendant merelymoves the opposite the upper end oi the plate F and they switch to itson position and then immediately returns it to its center position for aone-iloor run.

Assume now that the car overran its stop or that it drops, due to cablestretch in loading, while it is standing at the seventh iloor, say, morethan one-half inch below the oor level. This causes the car to bereleveled upwardly because when the car moves down the inductor relaycontacts IUL drop below the lower end of the inductor plate E so thatthey are free from the iniluence of the plate. Under these conditionsthe contacts IUL reclose and thus energize the up leveling relay LU toimmediately close its contacts LUI, thus energizing the up direction-switch U to close its contacts UI and U2 in the circuit of the patternfleld winding RPF, thus preparing it for up operation of the car. Theenergized switch U also closes its contacts U3 and U4 thus energizingthe car running relay M which, in turn, closes its contacts M4 thusreenergizing the auxiliary car running relay N. The energized relay Malso closes its contacts M3 thus completing the energization of thepattern eld winding 'RPF oi! the regulator to cause the starting of thehoisting motor for moving the car in the up direction. The energizedrelay N closes its contacts N2 thus completing the circuit through thebrake coil ISa and causing the brake I9 to be released so that the carmay be returned to its position level with the floor landing. Theenergized relay N also opens its contacts N3 and N4 in the circuit ofthe one-floor run relay 'I'A and the smooth start relay TC thuspreparing them for eventual operation after their time delay expires.

As the car moves upward in returning to its position level with theseventh oor landing, it carries the inductor relay L to the positionwhere its contacts IUL come opposite the lower end of the plate E andare again opened thus deenergizing the leveling relay LU which, in turn,opens its contacts LUI thus deenergizing the up direction switch U, thecar running relay M and the auxiliary car running relay N. Thedeenergized relay M opens its contacts M3 thus deen- I levelingoperation takes place when the car, for

any reason, moves below the oor level of the landing at which it isstopped. 1f the car should drift away from the floor in lthe updirection for any reason, the contacts HDL on the inductor relay L Wouldbe moved above the upper end of the inductor plate F and thereby causeenergization of the down leveling relay LD to return the car to itsiloor level. f

It will be assumed now that the attendant on the car again moves the carswitch to its down running position and leaves it there for a down runfrom the seventh floor to the fourth oor. This is more than a one-oorrun and, therefore, the operation of the one-oor run relay TA when ittimes out will have no eiect on the system. The movement of the carswitch for the down iloor run engages the contact 33 thus energizing thedown direction relay DR as previously described. The energized relay DRcloses its contacts DRS thus energizing the antiplugging relay TB, opensits contacts T133 thereby deenergizing the inductor relay L which causesthe closing of its contacts iUL, lDL, ZUL, 2DL and they, in turn,energize the up leveling relay LU, the down leveling relay LD, the lowspeed decelerating relay lP and the intermediate speed deceleratingrelay 2P, as previously described in connection with the one-floor runoperation.

The energized relay DR also closes its contacts DRB thus energizing thedoor relay K to eiect the closing of the car gate and the floor door(not shown) thus closing the gate and door safety contacts it and ilthus energizing the down direction switch D which, in turn, energizesthe high speed decelerating relay 3P and the car running relay M. Thecar running relay M energizes the auxiliary car running relay N which,in turn, deenergizes the time delay relays TC and TA and also energizesthe brake coil lSa to release the brake I9, all as previously-describedin connection with the one-floor run.

The timing relay, TC now times out after the expiration of .3 vof a.vsecond and energizes the high speed start relay GR which closes itscontacts GRl thus short circuiting the resistors rl,

18, r9 and rl@ in the pattern eld circuit of the regulator, which causesthe car to run at its normal high speed as previously described. Thedeenergized relay TC also opens its contacts TCE thus partiallypreparing the pattern field circuit for use when the car is to bedecelerated. Y

It will be recalled that the car attendant in making this more than oneoor run to the fourth floor keeps the car switch in its closed position.Therefore, the opening of the contacts TAI in the holding circuitprovided by those contacts for the down direction relay DR has no eiecton that relay.v

After the expiration of 1.8 seconds from the time the car was started,the one-floor run relay TA times out and opens its contacts TAI, butthis has no effect an the operation of the car because the car switchremains closed on its contact 33 which keeps the down direction relay DRenergized. A

When the car arrives at a position where it is from one-half to one oorabove the fourth oor at which it, is to be stopped, the attendantcenters the car switch CS to cause the car to stop at the fourth iloor.The centering of the car switch CS removes it from the contact 33 thusdeenergizing the down direction relay DR which closes its back contactsDRE and DRS and opens its front contacts DB2, DRl, DRE and DB6. Theopening of the contacts DRl deenergizes the high speed start relay GRwhich'opens its contacts GRI in its short circuit around the resistorsin the pattern neld circuit. inasmuch as the dec'elerating relays 3P, 2Pand iP are in energized condition, the resistors f8, r9 and rt@ stillremain short circuited but `the resistors rt and rl remain in thecircuit of the field RPF. This condition reduces the supply of energy tothe pattern field circuit and thus causes a reduction in the highrunning speed of the hoisting eld motor and the car and prepares the carto be decelerated to the stop at the fourth floor.

The deenergization of the relay DR by opening its contacts DRS alsodeenergized the anit-plugging relay 'IB which at the end of .3 secondcloses its back contacts TB and thereby energizes the inductor relay Lto effect deceleration of the car as it makes its down approach to theinductor plate E for the fourth oor. The operation of the inductorrelay, its contacts and l the decelerating relays controlled therebywill follow exactly as previously described in connection with thestopping of the car at the seventh oor while making its one-oor run.Hence no further description of the deceleration of the car will begiven.

This assumed operation illustrates how the 'system acts in making a morethan one-floor run.

This control system is designed to give a quick leveling action withoutreleveling in about 70% of the operations. All motoring loads `will cometo the oor quickly and without pause or overrun. Overhauling loads fromnearly empty car up to approximately 70% load down will come inlikewise. Empty car up and load down will usually overshoot the corabout one-half inch and relevel quickly. Full load down will overshootthe oor about three inches and relevel, provided in each case that thestarting switch is centered in time to permit retardation to highleveling speed before entering the leveling zone.

The action of coming into the oor quickly is obtained by making the highleveling speed (3P closed) and the retardation after entering theleveling zone (the inductor plate zone) just sumcent to cause the car tostop level with the floor. The speeds to which the car is decelerated bythe closing of the relays iP or 2P should be sulcient that, if the carovertravels the loor 7 inches or la inches or more, it will return at aspeed sumcient to prevent a pause coming to the oor and to preventovertravel of the floor. With these settings the car will never corneshort of the oor but will stop level or run past it. The operation ofreturning to the floor has been observed to be much faster than stoppingshort (pausing) and then continuing to the iloor.

The system is particularly suited to an elevator with a car having ahigh running speed of approximately 350 feet per minute, and in whichthe retention of the resistors r6 and r1 in the pattern circuit by theopening of contacts GRI will reduce the high-running speed of the car toa high decelerating speed of approximately 200 feet per minute as itmoves the inductor relay down to the inductor plate zone. Then as thecar enters the inductor plate zone, the high speed decelerating relay3P, the intermediate speed relay 2P, and the low speed relay IP aredeenergized in quick succession. This rapid weakening of the regulatorpattern iield combined with the strengthening of the dilerential eldproduces a rapid retardation which tests show will stop any car loadexcept the heaviest loads, level with the oor without overrun, underrunin any zone of approach at a regulated constant speed. It is believedthat this action is producedv through the slightly unstablecharacteristic of the regulator due to its abnormally strengtheneddiierential eld acting to produce a proportionately stronger retardationfor a loaded car than for a balanced car. Y

In operating 'this system, some variation in operation has been foundtraceable to changes in temperature. When the motor gets considerablyhotter than would be expected in normal operation, the car willovertravel approximately an inch and then return, where a cooler motorwould cause a level stop without overtravel.' It is anticipated thatcold conditions, such as may occur in some penthouses in the winter,will cause the car to stop short of every stop while the temperatureremains low.

I have provided a remedy for this by including a resistor in circuitwith one of the eld windings of the regulator and means forshort-circuiting that resistor to suit the Weather conditions. Theresistor may be included in either the pattern eld winding circuit or inthe loop circuit 22 connecting the self-exciting iield winding RCF andthe generator eld vwinding GF. In this instance I have included aresistor rl in the loop circuit 22 and have provided for its control bymeans of a push button 3| which may be located in the elevator car C foroperation by the car attendant. I have also provided a thermostat 34which may be mounted on the frame of the regulator and connected to socontrol the resistor rl in accordance with temperature conditions as tosecure the same degree of operation under various conditions oftemperature. The thermostat may be adjusted to short out a few ohms ofresistance to correct for the change in temperature when the frame heatsup a predetermined amount. In tests, it has been found that three ohmsare about the correct amount to short out. Normally, I supply aroundeight ohms `cold for the adjustment of the loop when the apparatus isinstalled and placed in operation.

The circuits for the system illustrated and described have purposelybeen shown in the sim- 4plest manner, omitting for simplicity the motorfield control, the discharge rectoxes around the leveling switch coilsand other places, and the safety circuit and door operating circuits, asthey may be readily supplied by any .one skilled m the art. The timerelays are indicated merely by cha e resistances. disAlthlogugh I haveillustrated and described only one specific embodiment of my invention,it is 75 to be understood that modifications thereof and changes thereinmay be made without departing from the spirit and scope of theinvention.

I claim as my invention:

l. In a control system for an elevator car serving a plurality oflanding iioors, a power generator provided with an armature and a eldWinding, a hoisting motor connected in a loop circuit with andcontrolled by said armature for operating the car; a regulator forenergizing and controlling the field winding of the power generator,said regulator having iield windings including a differential heldwinding; a switch, a control device, means responsive to a temporaryoperation of the switch for operating the control device, meansresponsive to operation of the control device for starting and runningthe car, means for controlling the regulator to decelerate the hoistingmotor, a timing device for maintaining the control device in itsoperated condition for a predetermined time after it is operated andthen causing it to be restored. to its unoperated condition, meansresponsive to the return of the control device 'to onoperated conditionfor rendering the accelerating means effective to cause the hoistingmotor to decelerate the car as it approachs the next i'ioor, and meansresponsive to operationof decelerating means for strengthening thedifierential iield to render the deceleration more eifective.

2. In a control system for an elevator oar serving a plurality oflanding floors, a power generator provided with an armature and a fieldwinding, a hoisting motor connected in a loop circuit with andcontrolled by said armature ior operating the car; a regulator forenergizing and controlling the field winding oi the power generator,said regulating generator including a diferential field winding; aswitch, a control device, means responsive to a temporary operation ofthe switch for operating the control device,

means responsive to operation of the control device for starting andrunning the car, means for controlling the regulator to decelerate thehoisting motor, a timing device for maintaining the control device inits operated condition for a predetermined period of time after it isoperated and then causing it to be restored to its unoperated condition,means responsive to restoration of the control device to its unoperatedccndition for rendering the decelerating means effective to cause thehoisting motor to decelerate the car as it approaches the next floor,means responsive to operation 4or' the decelerating means forstrengthening the differential eld of the regulator to render thedeceleration more elective, a releveling means for controlling the motorto relevel the car, and a time delay means responsive to the restorationof the control device to its unoperated condition for preventing thereleveling means from reversing the connections of the regulator for apredetermined time.

3. In an elevator system for operating a car serving a plurality oflanding floors, a switch, a car starting and running means, a controldevice responsive to a temporary operation of the switch for operatingthe car starting and running means, means for causing the car todecelerate and stop at a iioor, and a time delay device responsivetooperation of the car starting and running means for maintaining thecontrol device in operation for a predetermined period of time after itis operated and for then rendering time mechanism for maintaining theaccelerating means in operation for a predetermined time period and atthe end of said time period for rendering said accelerating meansineffective so that the car retards in speed; means responsive to theapproach of the carto a iioor for actuating said stopping means; wherebythe car will, in response to a temporary actuation of said car switch,start, accelerate to a high speed, retard to a low speed, and stopaccurately at a floor adjacent to the one from which the car started. v

5. A variable voltage system of control cornprising a power generatorprovided with an armature and a field winding and a motor connected in aloop circuit with said armature; a regulating generator for energizingthe field winding of the power generator, said regulating generatorhaving an armature, a series field winding, a differential fieldwinding, a self-exciting field winding, and a pattern field winding;control means for connectingthe pattern field winding to a source ofenergy to operate the motor at its high running speed, deceleratingmeans for controlling the regulator to decelerate the motor, and meansresponsive to operation of the decelerating means for strengthening thedifierential field of the regulator to render the deceleration moreeffective.

6. A variable voltage system .of control comprising a power generatorprovided with an armature and a field winding and a motor connected in aloop circuit with said armature; a

armature and a eld winding and a motor connected in a loop circuit withsaid armature; a regulating generator for energizing the field Windingof the power generator, said regulating generator having an armature, aseries field winding, a. differential field winding, a self-excitingielri winding, and a pattern field winding; decelerating means forcontrolling the regulator to decelerate the motor, a resistor disposedin series with the differential field winding, means responsive tooperation of the decelerating means for shortcircuiting a portion of theresistor to strengthen the differential field to render the decelerationmore eiective, a resistor disposed in series with the series fieldwinding. and means I responsive to operation of the decelerating means'regulating generator for energizing the eld winding of the powergenerator, said regulating generator having an armature, a series fieldwinding, a differential field winding, a self-exciting eld winding, anda pattern field winding; control means for connecting the pattern fieldwinding to a source of energy to operate the motor at its high runningspeed, decelerating means for controlling the regulator to deceleratethe motor, and means responsive to operation of the decelerating meansfor weakening the pattern field winding in rapid successive steps andstrengthening the differential field winding to produce a rapidretardation of the motor.

7. A variable voltage system of control comprising a power generatorprovided with an armature and a field winding and a, motor connected ina loop circuit with said armature; a regulating generator for energizingthe field winding of the power generator, said regulating generatorhaving an armature, a series field winding, a differential eld winding,a self-exciting field winding, and a pattern field winding; deceleratingmeans for controlling the regulator to decelerate the motor, a resistordisposed in series with the differential field winding, and meansresponsive to operation of the decelerating means for short-circuiting aportion of the resistor to strengthen the differential field to renderthe deceleration more effective.

8. A variable voltage system of control comfor short-circuiting aportion of the resistor in the series iield winding for strengtheningthe series field to )reep the regulator regulation at.

9. A variable voltage system of control comprising a power generatorprovided with an armature and a field winding and a motor connected is aloop circuit with said armature; a. regulating generator for energizingthe field winding of the power generator, said regulating generatorhaving an armature, a, series field winding, a differential fieldwinding, a self-exciting eld winding, and a pattern field winding;decelerating means for controlling the regulator to decelerate themotor, a resistor disposed in series with the differential fieldwinding, means responsive to operation of the decelerating means forshort-circuiting a portion of the resistor to strengthen thedifferential field to render the deceleration more e'ective, means forcontrolling the regulator to stop the motor, and means responsive tooperation of the stopping means for short-circuiting an additionalportion of the resistor to strengthen the differential field stillfurther for field killing purposes.

10. A variable voltage system of control comprising a power generatorprovided with an armature and a field winding and a motor connected in aloop circuit with said armature; a regulating generator for energizingthe field winding of the power generator, said regulating generatorhaving an armature, a series field winding, a differential fieldwinding, a self-exciting eld winding, and a pattern field winding;decelerating means for controlling the regulator to decelerate themotor, and means responsive to operation of the decelerating means forstrengthening the differential field of the regu- `'lator to render thedeceleration more effective and for strengthening the series field whenthe caris in the decelerating zone for keeping the regulator regulationfiat.

1l. A variable voltage system of control comprising a power generatorprovided with an armature and a field winding and a motor connected in aloop circuit with said armature; a regulating generator for energizingthe eld winding of the power generator, said regulating generator havingan armature, a series eld winding, a differential field winding, aself-exciting iield winding, and a pattern eld winding; deceleratingmeans for controlling the regulator to decelerate the motor, meansresponsive to operation of the decelerating means for strengthening thedii'erential field o the regulator to render the deceleration moreeffective and for strengthening the series field when the car is in thedecelerating zone for keeping the regulator regulation fiat. means forstopping the motor,

and means responsive to operation of the stopping means for furtherstrengthening the diiferential eld for neld killing purposes.

12. A variable voltage system of control comprising a power generatorprovided with an armature and a iield winding and a motor connected in aloop circuit with said armature; a regulating generator for energizingthe iield winding of the power generator, said regulating generatorhaving an armature, a series eld winding, a differential field winding,a self-exciting iield winding, and a pattern iield winding; controlmeans for connecting the pattern field winding to a source of energy tooperate the motor at its high running speed, decelerating means i'orcontrolling the regulator to decelerate the motor, means responsive tooperation of the decelerating means for strengthening the differentialfield of the regulator to render the deceleration more effective, andmeans for decreasing the resistance in a field winding of the regulatorfor compensating for a low temperature condition of the apparatus.

13. A variable voltage system of control comprising a power generatorprovided with an armature -and a field winding and a motor connected ina loop circuit with said armature; a

hregulating generator for energizing the field winding of the powergenerator, said regulating generator having an armature, a series fieldwinding, a diierential eld winding, a self-exciting field winding, and apattern field winding;

control means for connecting the pattern ileld winding to a source oienergy to operate the motor at its high running speed, deceleratingmeans for controlling the regulator to decelerate the motor, meansresponsive to operation of the decelerating means for strengthening thedifferential field of the regulator to render the deceleration moreeffective, and a thermostat associated with the regulator for decreasingthe resistance in a iield winding circuit for compensating for a lowtemperature condition of the apparatus.

14. A variable voltage system of control comprising a power generatorprovided with an armature and a iield winding and a motor connected in aloop circuit with said armature; a regulating generator for energizingthe field winding of the power generator, said` regulating generatorhaving an armature, a series iield winding, a difierential fieldwinding, a self-exciting iield winding, and a pattern eld winding;control means for connecting the pattern eld winding to a source ofenergy to operate the motor at its high running speed, deceleratingmeans for controlling the regulator to decelerate the motor, meansresponsive to operation of the decelerating means for strengthening thedifferential field of the regulator to render the deceleration moreeifective, and a manually operated switch for decreasing the resistanceina field winding circuit o! the regulator to compensate for a lowtemperature condition of the apparatus. l i

WILLIAM F. EAMES.

